Is it possible for him to become that rich in such a short time
Yes nothing is impossible with bitcoin when it comes to financial investment, El-Savador whole story about debt might have been cleared right before that eight years you thought, one thing with bitcoin as an investment is that it secures the future for you, there's no how you could make an investment in bitcoin over a long duration and never have a reason to smile at the end, it appreciate, its a digital good store of value, its an investment asset, its secured, its anonymous, if you look at the the history from how it all started from 2009 till date then you could get more conviction that El-Savador or you could achieve a big dream with bitcoin adoption and investment.
Finances on their own mean almost nothing. The basis of the development of any state is its economy. Material goods should be created in the country, all branches of the economy should develop, and gross domestic income should grow. And any currency only serves this process. Therefore, little depends on bitcoin in El Salvador. Without a proper organization of the growth of economic development, no currency will save El Salvador. Everything needs to be dealt with as a whole. Bitcoin can eliminate the shortcomings of the previous currency, although it is also not perfect. But it cannot replace the country's economic development.